2019 Volume 15 Pages A1-A14
There is little information on the population status or distribution of Swinhoe's Rail Coturnicops exquisitus in Japan. An effective survey method has not yet been established, and this contributes to the lack of knowledge about the species' ecology and distribution in Japan. We conducted a multi-year and multi-season survey using call playback to determine its population status in Ibaraki Prefecture, on the northeast coast of Japan. We conducted call playback method at 14 points within 12 areas, including a seemingly suitable habitat dominated by Carex spp., a short herbaceous plant, mixed with Phragmites spp., a tall herbaceous plant, in Ibaraki Prefecture from January 2016 to May 2018. The species was identified by analyzing spectrogram of the recorded calls, and by characteristic features of the birds flight from the call locations. We confirmed the species present at nine points within seven areas, and we recorded at least two individuals at five points within four of those areas. Based on those results we estimated that the population in the one of the areas was between 8 and 15 rails/ha in three winters. In a year-round survey, the rails were recorded from early November to middle or late April. These results indicate that Swinhoe's Rails regularly overwinter in Ibaraki Prefecture.
